Interpretive Summary: Hecker and coworkers demonstrated that sugar beet pollen could be stored at ultra-low temperatures for 1 yr and remained viable. In this study we demonstrate that similar pollen, stored for 17 years at (-160°C) was able to successfully pollinate sugar beet and produce viable seed. There were differences in the moisture contents of the stored and fresh pollen, but two tests showed no differences between stored and fresh pollen viability, and differences in pollen tube germination were small. Long-term storage of pollen provides opportunities for many uses both in the sugar beet plant genetic resources and plant breeding realms (which have considerable overlap). In a crop such as sugar beet with a large variation from plant to plant, collected pollen would be a way to preserve superior, individuals, which would have applied plant breeding applications and be useful in developing populations for genetic analyses. Collection and storage of pollen could be a way to obtain a more representative sample of the genetic diversity in wild populations. With restrictions on the international transport of seed becoming increasingly stringent, pollen could be an alternate way to distribute genetic resources or cultivated beet germplasm internationally.

Technical Abstract:
Hecker and coworkers demonstrated that sugar beet (Beta vulgaris, L.) pollen could be stored in liquid nitrogen vapor phase (-160°C) (LN) for 1 yr and remained viable. In this study we demonstrate that similar pollen, stored for 17 years in LN was able to successfully pollinate sugar beet and produce viable seed. There were significant differences in the moisture contents of the stored and fresh pollen, but two viability staining tests showed no significant differences between stored and fresh pollen, and differences in pollen tube germination were small. Long-term storage of pollen provides opportunities for many uses both in the sugar beet plant genetic resources and plant breeding realms (which have considerable overlap). In a heterozygous crop such as sugar beet, collected pollen would be a way to preserve superior, individual genotypes, which would have applied plant breeding applications and be useful in developing populations to facilitate genetic analyses. Collection and storage of pollen could be a way to obtain a more representative sample of the wild populations. With restrictions on the international transport of seed becoming increasingly stringent, pollen could be an alternate way to distribute genetic resources or cultivated beet germplasm internationally.